PSMB2 encodes a non-catalytic beta subunit of the 20S core proteasome complex that plays essential roles in protein degradation and cellular homeostasis. As a structural component, PSMB2 participates in both ubiquitin-dependent protein degradation through the 26S proteasome complex and ubiquitin-independent degradation when associated with regulatory particles like PA200 or PA28 1. The protein shows stable expression in bronchoalveolar cells across various lung diseases, making it useful as a reference gene for normalization in gene expression studies 2. PSMB2 demonstrates significant disease relevance, particularly in cancer. High expression correlates with poor prognosis in gastric cancer and glioma, where it promotes cell proliferation, invasion, and migration while suppressing apoptosis 13. In hepatocellular carcinoma, PSMB2 expression is regulated by alternative polyadenylation through NUDT21, contributing to tumor suppression mechanisms 4. The gene also shows involvement in lymphoma radiotherapy resistance when overexpressed 5 and plays a role in cardiomyocyte protection during hypoxia/reoxygenation injury through the LINC00339/miR-671-5p/PSMB2 axis 6. Additionally, PSMB2 is upregulated during bronchiectasis exacerbations, associated with neutrophil degranulation pathways 7, highlighting its broader involvement in inflammatory processes and cellular stress responses.